Air-mail exchange



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H0555 'CLlfFou dumm-4 Patented May 27, 1930 HOBBS E. CLIFFORD, OF KNIGHTSTOWN, INDIANA Ain-MAIL EXCHANGE Application led. February 8, 1929. Serial No. 338,582.

This invention relates to mail cranes of that class adapted to be used for transferring mail to and from an airplane while in flight and the prime feature of the invention is the pro- Vvision of a tower structure and means thereon for suspending bags of mail to be picked up by an airplane passing thereover.

A further feature of the invention is the provision of means, in conjunction with the bag suspending means, for. catching and retaining mail bags carried by the airplane.

A further feature of the invention is the provision of means on the airplane for picking upfrom and delivering` bags to the bag suspending means of the tower structure.

A further feature of the invention is the provision of a revolving part for the tower structure at the upper end of which is formed a turret in which the bag suspending and catching means is positioned when a delivery orcollection is to be made.

A further feature of the invention is the provision of air cont-rolled means for retaining the turret hea-ded into the wind at` all times.

A further feature of the invention is the provision of beacon lights so arranged that they will illuminate the interior of the turret and form a guide for the airplane when de- 30 livering and picking up mail bags.

A further feature of the invention is the provision of means for disposing the bag suspending means into operative or inoperative positions from the base of the tower or interior of the airplane.

A further feature of the invention is the provision of yielding suspending and catching means to guard against injury to the mail bag or parts of the mechanism in eventof an imperfect connection between the tower and airplane.

A further feature of the invention is the provision of shock absorbing means in connection with the bag suspending and delivering mechanism for cushioning the jar on the bags incident to their delivery from and pick up by the airplane.

A further feature of the invention is the provision of conveniently operated means for securing the mail bags to the suspending elements therefor.

Other objects and advantages will hereinafter more fully set forth and pointed out in the accompanying specification.

In the accompanying drawings which are made a part of this application,

Figure l is a side elevation,- partly in section and partly broken out, of an airplane in the act of picking up and delivering mail.

Figure 2 is an enlarged detail sectional view showing the `catching and delivering mechanisms efthe tower structure and airplane in operation.

Figure 3 is a perspective view of the de- 65 livering and catching mechanism of the airplane in operative position. K v

Figure 4 is a vdetail perspective view of the catching and delivering mechanism of the tower structure.

Figure 5 is a detail to plan view of the atching and delivering mechanism shown in Figure 6 is a detail elevation of the turret portion of the tower structure.

Figure 7 is an enlarged sectional view as seen on line 7-7, Fig. 1. n

Figure Sis an enlarged elevation of the lower end of the tower structure.

Figure 9 is a perspective view of the base portion of the revolving portion of the tower structure.

Figure 10 is a plan view of the platform or turn table at the upper end of the fixed portion of the tower structure. 85

Figure 11 is a sectional view of one of the hangers for the mail bags, parts being shown in dotted lines, and,

Figure 12 is an edge elevation, with parts in section, of the lower end of the bag hanger. 9U

Referring to the drawing in which similar reference-numerals designate corresponding parts throughout the several views, 1 indicates a tower structure, whichmay be constructed of any suitable material, preferably- 95 angle iron, and is preferably mounted lon a base of concrete or the like 2, which may be a part of the floor structure'of a building 3, or may be of sucient size to receive the tower structure, 90

`to the upper end of the tower structurel proper. Anysuitable antifriction members,` such as bearing balls 8, may be introduced'l f, between the floor of the/turret'and platform,

Extending vertically through the central portion of the tower structure l is a frame structure 4, the lower end of which is xed to a rotating base 5, while the upper end thereof isprovided with a turret 6, the under face of which rests over a platform 7 attached to reduce friction between these parts during the rotating action of the frame 4.

The roof 9 of the turret is preferably arcuate, so that a suspendedarticle'striking thereagainst will slew over the roof without becoming entangled therewith', said turret having a passage-way 10, transversely 'therethrough as shown in `Fig. A6, through which the mail bags may pass on entering or leaving the turret. u

In order toldispose a mail bag 11 in posiL tion tobe picked upby an airplane 12, while in flight, 'a Vrack 13 is provided, consisting of a plurality of .spaced fingers 14, the inner I ends of which are pivoted to a rod 15, ex-

tending transversely 'through the rack, said fingers being arcuately curved and with their free ends tapered's'o that an object will read* ily. enter vbetween or leave the lingers, the

concaved faces of the fingers serving to hold the bag againstcasu'al disengagement from the rack.V By pivoting the fingers 14 in this manner, should-the `bags become `fouled withl the fingers, said fingers willv swing upwardly andrrelease the fouled bags,` the 'curvature-of thev fingers aiding in Areleasing -the fouledV bags. y

The-rack- 13 is supporteda distance above a disc 16 by means of rods 17, said rodsbeing pivoted attheir upper ends to the ends of the yrack 13 while their lower ends are piv- `oted to the disc 16,thus allowing lateral' the postsQOof the frame structure 4, the disc. havingnotches 2,1 in its edge for the reception of the posts120 and by which means the disc is held against rotation independently of the frame, althoughit kmay be moved from the topto'fthebottom of the frame.` The vertical movement ofthe disc 16 and rack 13carriedf thereby-.is controlled. through the ine--v dium of a-windlassv22, mounted onthe rotating'base, cable23 Abeing extended around sheaves 24 on the windlass and sheaves 25 at the upper end of the frame 4 with theirends attached to the disc 16. In this manner7 when the windlass is rotated in one direction, the disc and parts carried thereby will be elevated and will be lowered when the windlass is rotated in the opposite direction. The windlass is normally held against reverse rotation by'means of a ratchet and pawl mechanism 26.

Theb'ase 5 is swiveled on a post 27, the

@lower end of which is preferably anchored in the concrete base 2, and if desired a nut 28X-may be threaded onto the upper end of the post 27, thus more securely anchoring the base-5 in position.

ln. suspending a bag 11y from the rack 13, a 'hanger rod 29'is provided, having'at its lower end a forcep like gripper 3Q one awv of which is fixed to the rod 29 and the other jaw pivoted thercto,"a sleeve 31 being slidably inounted'on the rod for locking the jaws in closed position whenv engaged with a loop 32 on the bag 1 1. VThe rod 29 is provided with'A buttons 33 and`34 in its lei'igth,one of which is adapted to restupon adjacent-'lingers 14, when the rod is passed between a pair of the fingers, while the otherbutton is designed toent with the fingers 35 of a companion rack inember 36, carried by the air plane 12;

'The rack member 36 is constructed similar to the rack member 13, and is suspended beneath an'air plane 'by means of jointed bars 37, the joints 33 being so arranged that. the sections of the bars can not assume a straight line, by which means, said bars will fold together when anupward pull is made'on'the"- rack inember'36, as indicated in dotted'linesy- Fig. 2. Therack member 36is raised and lowerediloyv means ofV cables 39, theends ofwliich'are attached to the ends 'of the rack member 36, saidcables extending thence; over sheaves 40 in the 'bottomwallof the air plane, and into engagement' with a winding drum 41 wit-hin the air plane. The floor of the air plane is provided with trap doors 42, which are manipulated by means of 'a lever 43, said doors to be opened when access to therack member is to be had and closed when in flight and no mail is being delivered or collected.

ln order to keep thev turret headed into'the wind at all times, a ,rudder blade'44 is attached to the base of the turret at. one end of the passage wayf10, so that a plane approachvingfsaid turretwill always beheaded into* the wind,- a shield 45l extending outwardly fromth'e turretftoprevent the Imail' bags .depending from the plane striking or becoming entangled Vwith theruddcr. f' At the opposite endnof' the `passage way 10 Ais provided a counterba-lance weight 46,-which aids the rudder 44 iii-maintainingfthe turret headedinto the wind.

The passageway 10 is illuminated by means oflanips 47, whichare arranged beneath the top edges of the turretG and so constructed that a ray of light will bev cast from each side ioe of the turret onto the mail bags suspended therein, as indicated at 48, while two other rays of light 49 will be cast upwardly in crc-seing relation, to indicate to the occupant of the air plane the exact height the plane must be Vflown to make proper connections with the suspended bags.

The rods 29 are preferably constructed in two sections 50 and 51, the section 51 being hollow for the reception of the section 50, a coiled spring 52 being disposed around that portion of the section 59 within the section 51 and between a head 53 on the inner end of the section 50 and a cap 54 threaded on the end of the section 51. The object in constructing the rods in this manner is to compensate for the impact necessarily incident to the removal or deposit of the mail bags with the racks 13' and 36, the tension of t-he springs 52 being such as to practically absorb the shock of the impact before it reaches the racks.

The top ends of the sections 50 are provided with eyes 55, with which are to be engaged hooks 56 carried by a pull cable 57, so that the bags 11, picked up by the rack 36 may be drawn into the plane 12, said cable passing` over sheaves 58, as shown in Fig. 2,

the fingers 35 swinging upwardly, as indicated by dotted lines, to permit the bags to pass through the opening formed by the forward t-rap door 42, and into the interior of the plane 12.

In operation, when mail is to be picked up by the air plane, one or more bags 11, are suspended from the rack 13, by firstattaching a hanger rod 29 to each bag by means of the gripper 3() and loop 32 and said rod then entered between a pair of said fingers 14,

the lowermost button 34 resting on the top curved faces of said fingers and the button 33 extending a distance above the. fingers and in position to be engaged by the fingers of the rack member 36 of the air plane, the bags being placed in engagement with that end of the rack 13 towards the wind. The rack 13 is then elevated into the turret 6 by operating the windlass mechanism 22, the pawl and ratchet mechanism 26 preventing reverse movement of the rack 13.

If mail is to be delivered from the plane, the rear most trap door 42 in the plane'is raised and one or more bags suspended from the rearmost set of fingers on the rack 36 and said rack then lowered, through the medium of the winding drum 41, until the rack 36 is in its lowermost position. In making a delivery or collection of mail, the air plane is headed into the wind and towards the turret 6 and, by heading t-he plane directly at the point of crossing of the rays of light 49, from the lamps 47, the plane will be at exact-ly the right height to make deliveries to and collections from the rack 13, the forward fingers of the rack 36 passing beneath the button 33 and suspending the bags 11 therefrom, while the rearmost fingers 14 of the rack 13 will engage the buttons 34 on the rods 29 suspended from the rack 36 and suspend the bags from the rack 13, these exchanges being made while the plane is still in flight. After the exchange has been made, the rack 13 is lowered to the bottom of the frame structure 4 and disposed of in the usual manner, while the mail picked up by the plane is brought to the bottom of the plane by elevating the rack 36, and the bags thenfremoved therefrom through the openingy formed by the forward trap door 42 by engaging the hook 56 with the eye 55 on the rod 29 and then directing a longitudinal pull on the cable 57 untilthe bag is drawn within the plane 12, this being accomplished without interrupting the flight of the plane. y

While I have illustrated in a general way, certain instrumentalities which may be employed in carrying my invention into effect, it is evident that many modifications may be made in the various details, without depart- Y ing from the scope of the appended claims, it being understood that my invention is not restricted to particular forms, herein described.

VV hat l claim is: 1. In an airmail exchange, va tower structure, an article suspending rack associated therewith, means for positioning said rack Y at either extremity of said tower' structure, and means associated with an aerial craft adapted to remove articles from said article supporting rack and deposit other articles thereon when the first rackpis moved to the upper extremity of said tower.

42. In an air mail exchange, a tower structure, a rotating frame therein, a rack associated therewith, means for moving said rack through the interior of said tower to either extremity thereof, means for suspending articles form the rack, a rack associated with an aerial craft, means for raising and lowering the same, and means forl suspending articles from the second rack in position to be deposited on the iirst rack,as the air craft passes thereover.

3. In an air mail exchange, a tower structure, a turret thereon, means on the turret adapted to support bags of mail in position to be picked up by an air craft and collect bags suspended from said air craft, while the craft is in Hight, and means for automatically A anduthe passageway therethrough intov the wind'. i f

5. Inan air mail exchange, a tower structure, a frame; rotatably mounted within said tower, a turrety attached to the upper end of said frame, said turret having a passagewaylthcrethrough, means for heading said turret and passageway into the wind, a bag supportingk rack vertically slidable in and ,rotatable :with said frame, and' means for disposingsaid rack into said turret in positionto deliverb'ags suspended thereon to an air craft and receive bags from the air Vcraft while the craft is in flight. 1

6. .In an air mail exchange, a tower structure, a frame structure associated therewith, and a bag supporting rack associated with said frame comprising rigid end sections, a rod connecting said end sections, and a pluralityr of fingers hinged to said rod'.

v7. In an air mail exchange, a bag supporting rack associatediwith an air craft, expansible -or collapsibleV Ameans between said air craft vand rack for extending said rack into position to deliver and receive bags when expanded and while the craft is in flight, and

for positioning said rack in inoperative position adjacent the body of the air craft when collapsed. A

8. In'an air mail exchange, a bag supporting rack carried by an air craft, expansible or `collapsible means between the aircraft and rack for extending said rack a distance below the air craft when expanded or in juxtaposition to the body thereofwhen collapsed, and manua-lly'operated means within the air craft for removing bags@ from the rack to the interiorl ofthe air craft.

9. In` an air mail exchange, a tower structure, a bag supporting rack associated therewith,supporting rods for said bags said rods being formed in sections, cushioning means between the sections of the rods for assimilating fshocl, 'means for suspending the rods from fthe rack, and means for removably-attaching the rods to the bags: f

10; Inv an air mail exchange, av frame structure, a disc vertically slidable in said frame structure, a bag supporting rack above said disc, andmeans for flexibly mounting said rack on'said disc. i

`11. In an air mail exchange, a frame structure, a bag supportingrmeansvertically slidablerthrough said frame structure, and yielding means for normally retaining said bag supporting means .in fixed upright position and Vpermitting said bag supporting means to move laterally under impact.

12.l In an air mail exchange, a tower struc- Y ture, an article supporting means movable therethrough adapted to be disposed and support the articles above the upper end ofsaid towerl structure, and `means on said tower .structure for preventing articles suspended -from? anapproaching air'u'craft becoming fouled on the article supporting. element when a wrong approach ismade bythe air craft.

In testimony whereof,'I-have hereunto set,V

my hand on this the 31st day of January, 1929, i 

